A wide variety of product characteristics must be given attention in order to provide a tissue product with the appropriate blend of attributes suitable for the product's intended purposes. Contributing to this variety is the vast array of different product forms, such as facial tissue, bath tissue, napkins, and towels. Regardless of product form, however, improved softness of the product has long been one major objective, especially for premium products. In general, the major components of softness include stiffness and bulk, with lower stiffness and higher bulk generally improving perceived softness.
A throughdrying process can be used to improve the bulk of tissue products. Throughdrying is a relatively noncompressive method for removing water from a web. Specifically, a wet laid web is transferred from a forming fabric to a coarse, highly permeable throughdrying fabric and retained on the throughdrying fabric until it is dried by hot air passing through the web.
Throughdried sheets can be quite harsh and rough to the touch, however, due to their inherently high stiffness and strength and also due to the coarseness of the throughdrying fabric. For this reason, creping has been used to improve the softness of throughdried tissue sheets. Creping removes some of the stiffness of the uncreped sheet, albeit at the expense of the sheet strength.
Despite the improvements in softness that can be gained from creping, however, additional improvements in softness would be beneficial to consumers. Therefore, what is lacking and needed in the art is a process for further improving the softness of creped throughdried tissue products.